Mutations of Photosystem II D1 Protein That Empower Efficient Phenotypes of Chlamydomonas reinhardtii under Extreme Environment in Space
Figure 1
Real-time monitoring of fluorescence emission of C. reinhardtii strains during the Foton flight mission.
The parental strain IL and its D1 mutants were sent into space inside the re-entry module of the Russian spacecraft Foton M2 capsule aboard Soyuz-U rockets launched from the Baikonur Cosmodrome in Kazakhstan. A multisensor fluorimeter specifically developed to accommodate the Chlamydomonas strains monitored fluorescence emission during the space flight and in ground control experiments as described in methods. The algal strains were grown in liquid TAP medium with 150 rpm agitation under a white light (50 µmol m−2 s−1) at 25°C. Cells in mid-exponential growth phase (A750nm = 0.4) were harvested by low speed centrifugation, re-suspended in 150 µL of TAP medium in order to reach A750nm = 18 and layered on TAP medium containing 1.65% agar. The organisms were exposed to a 17 h darkness and 7 h 50 µmol m−2s−1 daily cycle in the biocells of the fluorometer. Time zero refers to the take-off. Days 0 to14 refer to the flight period. Day -1 refers to 1 day before the take off. Pink, in-flight analysis; blue, cells analyzed on ground under simulated temperature and light conditions of the space mission.